Power switch symbol on schematic

I have a Sunn Beta Lead guitar amp (100 W solid state) that I have a couple quick questions about - hoping someone can help out:

- in the schematic, there is a symbol that looks like a capacitor with a circle around but no values -- it connects between one pole of the power switch to the white wire from the power cord. What is this thing? (I think the power switch was replaced at some point - it doesn't fit in the chassis hole properly and I don't see this mystery component anywhere.) Also, the loose wire is connected directly to another wire (white wire from power cord directly to black wire on transformer).

- when I power down the amp, there is a very loud pop. (I think I've blown two speakers because of this now). Could this be related to the missing mystery component? (Is this a "snuffer cap," which I've read about on these forums?)

Here's a link to a schematic:
(see lower left corner)

Thanks a lot in advance --


Paid Member
2004-06-06 8:31 pm
Georgetown, On
It sure looks like a neon. And it being gone will not hurt a thing. There should be a resistor in series with it if it were a neon. So I think it's an AC outlet on the back.

From looking at the diagram I would say the turn off "pop" is normal. I doubt it would blow a speaker. To reduce it, install an MOV across the primary of the transformer to clamp the turn off spike. V130LA10A or similar for 120 VAC circuits.